Electric wrist watch movement



A. CACHIN ET AL 3,111,806

Nov. 26, 1963 ELECTRIC WRIST WATCH MOVEMENT Filed April 17. 1961 2Sheets-Sheet 1,

FIG] Nov. 26, 1963 A. CACHIN ET AL ELECTRIC WRIST WATCH MOVEMENT 2Sheets-Sheet 2 Filed April 17. 1961 FIG. 5'

United States Patent Ofi ice 3 ,1 l 1,8 -5 Patented Nov. 26, 1963ELECTREC WRIST WATCH MOVEMENT Andre (Iachin and Marc Nardin, both ofSaint-iinier, .l'ura Eerneis, Switzerland, assignors to Compagnie tiesMontres Longines Francillon S.A., Saint-Imier, Switzerland, a Swiss firmFiled Apr. 17, 1961, Ser. No. 103,653

Claims priority, application Switzerland Apr. 20, 1966 3 Claims. (Cl.58-28) The present invention generally relates to electric drivingmovements and more particularly to an electric wrist watch wherein themovements of the balance wheel are maintained by mechanical impulsestransmitted to it by the movable element forming part of the drivingmove ment including a winding to which are applied periodically electricimpulses.

The chief difficulty met hitherto by watchmakers in the execution ofsuch electric watches consisted in that it was a diflicult matter tofind a compromise between the technical conditions required forobtaining a good efiiciency and a sutiicient reliability in operationfor the movement, on the one hand, which means that comparativelylargesized driving means or movements are to be used and, on the otherhand, the aesthetic conditions which require a watch of a reduced size.

The solutions proposed hitherto for said problem in the case ofconventional movements are not satisfactory. They sacrifice theaesthetic appearance of the watch. As a matter of fact, it the movableelement pivots round an axis parallel with that of the balance wheelafter the manner of conventional movements, there are only two ways ofpositioning the driving means. Either, it is arranged between the plateand the balance wheel, so that the thickness of the watch becomesexaggerated, or else, it is housed inside the balance wheel and thewatch assumes an unallowable transverse size.

The present invention has for its object a solution of the problem, witha view to satisfying both the technical and aesthetic conditions of theproblem.

According to the invention, the wrist watch includes a movementcomprising a movable element mounted on the watch plate in a manner suchthat it may pivot round an axis perpendicular to the axis of oscillationof the balance wheel. This arrangement allows, in particular,positioning the entire driving movement inside a normally empty spaceextending between the plate and the balance wheel.

The accompanying drawing illustrates, by way of example a drivingmovement in accordance with two preferred embodiments of the invention.In the drawing:

FIG. 1 is a plan view of a first arrangement, while FIGS. 2 and 3 arecross-sectional views taken through line ll-II and III-J11 of FIG. 1.

FIG. 4 is a plan view of a second embodiment.

FFG. 5 is a cross-sectional view through line V-V of FIG. 4.

In the first arrangement illustrated in FIGS. 1 to 3, It) designates thebalance wheel of the watch, 13 the balance staff, 12 the regulatingspiral adjusting spring, 13 the main plate, 14 the balance cock, 15 thetrain wheel bridge, 16 the first gear of the time train, 17 and 18 theprojecting contact and the contact blade of a switch 6%) which closes atthe moment at which the balance wheel passes in a predetermineddirection through its position of static equilibrium.

The maintenance of the oscillatory movement of the balance wheel 1i andthe drive of the train are ensured by a galvanometric system, of whichthe magnetic circuit is constituted by a permanent magnet 19 and a core20, made for example of mild steel or a magnetic alloy extending insidethe air gap of the magnet. The core 20 which is secured to the plate 13by a screw 21 carries two coaxial rings 22 and 23 forming the carriersfor two throughstones 24 and 25.

The movable element of the movement is constituted by two U-shapedsupports 26 and 27 provided with pivots 28 and 29 revolvably carried inthe throughstones 24 and 25 and by a rectangular winding 30, the longersides of which rock in the air gaps extending between the poles of themagnet 19 and the core 2%, while the small sides thereof are fittedinside the supports 26 and 27.

Along the axis of the pivots 28 and 29 and on the outside of the movablesystem or movement, the U-shaped supports 26 and 27 carry twocontact-making projections 31 and 32 connecting electrically through twoelastic blades 33 and 34 and a switch 60, the two ends of the windingwith a supply of electric energy 35.

The U-shaped support 26 also carries a spring-biased catch 36cooperating with the ratchet wheel forming the gear 16 and a blade 37made, for example, of a mild steel, or magnetic alloy. The movableelement may rock between two stops 38 and 39 formed by two screwscarried by the plate 13. It is urged magnetically against either of thestops according to whether it lies to one side or the other of itsmedial position, as provided by the magnetic action exerted by themagnet E9 on the blade 37.

When the balance wheel rocks, the movable element rocks periodicallybetween the stops 38 and 39 under the mechanical action of a projection40 on the balance wheel which engages, when the latter passes throughits position of static equilibrium, the inside of a transverse groove 41formed in the U-shaped support. When the rocking movement is executed ina predetermined direction, the switch 66 closes and the winding 30 istransiently energized. The movable element is then subjected to 'atorque which produces an acceleration of its rocking movement and thetransmission of a mechanical pulse to the balance wheel. The pulse notonly serves to maintain the movement of the balance wheel, but it alsoserves to intermittently drive the gearing through the catch 36 and theratchet wheel 16.

The second embodiment illustrated in FIGS. 4 and 5 distinguishes fromthat described hereinabove in that the core 20 is hollow and is rigidwith the winding 36. The pivots 24 and 25 for this movable element inthe second embodiment are secured to the small sides of the winding andrevolve inside bearings 42 and 43 secured to the plate 13. The ends ofthe pivots, which project beyond the outer surface of the bearings, aretapered and play the parts of the projections 31 and 32 in the firstembodiment. The groove 4-1 is, in this case, replaced by a notch 41formed in a member 44 secured rigidly to the core 2%.

In the second embodiment, there are also provided means for preventingany fortuitous reversal of the movable element when the balance wheel isspaced with reference to its position of static equilibrium. For thispurpose two projections 45' are provided on the member 44 and a plate 46is keyed to the balance staff 11.

hen the balance wheel is at a distance from its position of staticequilibrium, these two projections 45, lying on either side of theplate, lock the movement element in position. In order to allow amodification in the position of the projections, upon reversal of themovable element, the plate 46 is provided with a notch 47 registeringwith said movable element when the latter is in its reversing position.

Otherwise, the operation of the second embodiment is the same as that ofthe embodiment illustrated in FIGS. 1 to 3.

What we claim is:

l. In an electric timepiece, an improved electric driving movementcomprising, a regulating balance wheel for, oscillating around an axisof rotational oscillation through a position of static equilibrium, atime train, a magnet having an air gap; a coil mounted in said air gapand having diametric portions extending therebeyond, said coil beingpivoted around an axis through said diametric portions and normal to theaxis of rotational oscillation of said balance wheel, one said diametricportion extending beneath said balance wheel and the other extendingbelow said time train, electric power means for energizing said coil,circuit means including means controllable by the balance wheel at saidposition of static equilibrium for connecting said electric power meansto said coil, and thereby causing said coil to pivot back and fortharound said axis through said diametric portions of said coil, stopmeans for limiting the pivoting equally on each side of a mean pivotposition, first complementary means carried by said balance wheel andsaid one diametric portion of said coil for mechanically engaging saidbalance wheel with said coil, and second complementary means carried bysaid time train and said other diametric portion of said coil formechanically engaging said time train with said coil for driving saidtime train and said coil, said balance wheel and said time train therebybeing disposed to maintain the radial and thickness dimensions or" saiddriving movement to a minimum.

2. An improved electric driving movement according to claim 1 in whichsaid first complementary means comprises a U-support mounted around saidone diametric portion of said coil, said U-support defining a grooveadjacent said balance wheel, and a pin depending from said balance wheeland positioned to engage in said '4. groove when said balance wheel isin said position of static equilibrium and said coil is in said meanpivot position.

3. An improved electric driving movement according to claim 1, in whichsaid first complementary means comprises a notched plate positionedabove said one diametric portion of said coil, said notch beingpositioned symmetrically in the plane of said axis through saiddiametric portions, said notched plate having two projections extendinglongitudinally from said plate and positioned symmetrically with respectto said notch located therebetween, a pin depending from said balancewheel and disposed to engage in said notch when said balance wheel is insaid position of static equilibrium and said coil is in said mean pivotposition, a circular plate keyedto oscillate rotationally with saidbalance wheel to pass between the projections of said notched plate whensaid coil is not in its mean pivot position, said circular plate havinga sector removed from its periphery adjacent said projections when saidcoil is in said mean pivot position and said projections and said plateare in the same plane, whereby said circular plate passing between saidprojection prevents an accidental reversing of said pivoting coil.

References Cited in the file of this patent UNITED STATES PATENTS1,112,747 Wingo Oct. 6, 1914 2,420,827 Kennedy May 20, 1947 FOREIGNPATENTS 9,832 Great Britain Apr. 21, 1915 of 1914 1,144,213 France Apr.23, 1957

1. IN AN ELECTRIC TIMEPIECE, AN IMPROVED ELECTRIC DRIVING MOVEMENTCOMPRISING, A REGULATING BALANCE WHEEL FOR OSCILLATING AROUND AN AXIS OFROTATIONAL OSCILLATION THROUGH A POSITION OF STATIC EQUILIBRIUM, A TIMETRAIN, A MAGNET HAVING AN AIR GAP; A COIL MOUNTED IN SAID AIR GAP ANDHAVING DIAMETRIC PORTIONS EXTENDING THEREBEYOND, SAID COIL BEING PIVOTEDAROUND AN AXIS THROUGH SAID DIAMETRIC PORTIONS AND NORMAL TO THE AXIS OFROTATIONAL OSCILLATION OF SAID BALANCE WHEEL, ONE SAID DIAMETRIC PORTIONEXTENDING BENEATH SAID BALANCE WHEEL AND THE OTHER EXTENDING BELOW SAIDTIME TRAIN, ELECTRIC POWER MEANS FOR ENERGIZING SAID COIL, CIRCUIT MEANSINCLUDING MEANS CONTROLLABLE BY THE BALANCE WHEEL AT SAID POSITION OFSTATIC EQUILIBRIUM FOR CONNECTING SAID ELECTRIC POWER MEANS TO SAIDCOIL, AND THEREBY CAUSING SAID COIL TO PIVOT BACK AND FORTH AROUND SAIDAXIS THROUGH SAID DIAMETRIC PORTIONS OF SAID COIL, STOP MEANS FORLIMITING THE PIVOTING EQUALLY ON EACH SIDE OF A MEAN PIVOT POSITION,FIRST COMPLEMENTARY MEANS CARRIED BY SAID BALANCE WHEEL AND SAID ONEDIAMETRIC PORTION OF SAID COIL FOR MECHANICALLY ENGAGING SAID BALANCEWHEEL WITH SAID COIL, AND SECOND COMPLEMENTARY MEANS CARRIED BY SAIDTIME TRAIN AND SAID OTHER DIAMETRIC PORTION OF SAID COIL FORMECHANICALLY ENGAGING SAID TIME TRAIN WITH SAID COIL FOR DRIVING SAIDTIME TRAIN AND SAID COIL, SAID BALANCE WHEEL AND SAID TIME TRAIN THEREBYBEING DISPOSED TO MAINTAIN THE RADIAL AND THICKNESS DIMENSIONS OF SAIDDRIVING MOVEMENT TO A MINIMUM.